Rich blue, internally flawless blue sapphire, weighing 423 ct, is perhaps the second largest blue sapphire in the world. Since ancient times, Sri Lanka has prohibited the export of rough rocks. Originally found and cut Logan sapphire in Sri Lanka, which boasts over two centuries of cutting and mining industries. The sapphire cushion cut displays violet overtone. According to the GIA’s 1997 statement, the color of the Logan sapphire is purely natural and there was no evidence that the stone is heat treated. The stone shows moderate reddish orange florescence under ultraviolet radiation. This rock is currently on display at the Natural History Museum of the Smithsonian Institution.Blue Sapphire is one of the classic colored gemstones and is always in fashion. It is valued for its vivid color, its excellent hardness (9 on the Mohs scale) and its rarity. Collectors and investors search out particularly fine specimens, which have historically increased in value over time.
Blue sapphire colors range from pale blue to cornflower blue to royal blue, navy blue and midnight blue. The main sources are Sri Lanka (Ceylon), Burma (Myanmar), Madagascar, Tanzania, Australia and Thailand. At one time exceptional sapphires came from Kashmir, but no new material has been found there for about 100 years.